for number ten, you just need to write ANYTHING literally ANYTHING be it multiplication, division, addition, subtraction, but make sure they are in a parenthesis and you multiply by 0 outside the parenthesis.
example: 0(3+2346)
why? well because anything multiplied by 0 is equal to 0
11. just substitute X3
8(1)+ 3(6)
8+18=26
12...... 2+w maybe.... i don't really know about this one it's been years lol
13. same as ten, but try substituting w for another variable or number, or try changing the 6 for another number, remember it can be ANYTHING as long as you multiply by zero OUTSIDE the parenthesis.
sorry that i wasn't able to help you at all on number 12.